The present invention relates to a gateway between two networks making it possible for the services contained in the applications servers situated in a first network to transmit commands for modifying the behavior of the second network, and to receive information therefrom, without knowing the topology or the specific protocols thereof.
The invention is particularly applicable to the case of an intelligent network (IN), e.g. as defined by the Q.1200 series of recommendations by the ITU-T (International Telecommunications Unionxe2x80x94Telecommunications Standardization Section). The basic principle of the intelligent network is to separate the data-conveying (and in particular voice-conveying) functions from the supplementary services. This general principle has resulted in a hardware architecture such as the architecture shown in FIG. 1.
In FIG. 1, references C1, C2, C3, and C4 represent switches, i.e. nodes of the transport network which is drawn in solid lines in FIG. 1. Using the terminology specific to intelligent networks, the switches are also referred to as Service Switching Points (SSPs).
The switching points or xe2x80x9cSSPsxe2x80x9d are connected to one or more Service Control Points (SCPs).
In FIG. 1, reference S1 illustrates one such SCP. The various services of the intelligent network are stored in the SCPs. By way of non-limiting example, the following services can be proposed:
special charging services (collect charging, shared charges, etc.);
customized call-filtering services; and
call forwarding services.
Reference P1 represents an intelligent peripheral (IP). An intelligent peripheral is typically a voice machine on which some spoken announcements are pre-recorded for the purpose of being delivered to a user of the network when a service is requested. Optionally, the intelligent peripheral makes it possible to interact with the user by enabling the user to enter a combination of keys on a telephone set or handset, which combination is then transmitted to the service.
The dashed lines show the signalling network, i.e. the network making it possible for all of the components of the intelligent network (C1, C2, C3, C4, P1, S1) to communicate with one another, independently from the transport network. In particular, the signalling network is used for conveying the messages for setting up a temporary connection between the SSP of a user and an intelligent peripheral, on the request of a service contained in an SCP.
In an intelligent network complying with the recommendations of the Q.1200 series from the ITU-T, the signalling protocol that is implemented between the service control point (SCP) and the network elements (i.e. switching points and intelligent peripherals) is the Intelligent Network Application Protocol (INAP) that is usually implemented on top of a stack of SS7-type protocols as defined by the Q.700 Recommendation by ITU-T.
It is also possible to use other protocols without adversely affecting the architecture or the principles of the intelligent network. Other protocols that can be used are constituted by proprietary protocols specific to suppliers of equipment for telecommunications networks.
In order to operate properly, certain services require the use of intelligent peripherals. For example, that applies to a service requiring the calling user to be authenticated. When a user uses such a service, the service connects the user initially to an intelligent peripheral serving the following purposes:
welcoming and guiding the user by means of suitable spoken announcements;
collecting the data necessary for authentication (personal identity number, etc.); and
transmitting them to the service.
The intelligent peripheral in question may be integrated in the SSP of the user, or it may be connected directly thereto, or else it may be associated with another switching point and thus be accessible via the network only.
It can thus be observed that, in order to connect the user to the intelligent peripheral, the service must know firstly the location of the intelligent peripheral that is most suitable, using some particular criterion (e.g. the SSP that is closest to the user), and secondly the communications protocol that makes it possible to set up a connection with the intelligent peripheral.
That gives rise to two major drawbacks:
Firstly, it means that when a new service is being developed, account must be taken both of the architecture of the associated transport network, and also of the signalling protocol(s) implemented.
Secondly, it means that the operator of the transport network must make public its internal architecture as well as the protocols that it implements in order to offer services external to the operator. That constraint can be draconian for the operator.
An object of the present invention is to make the services independent from the architecture of the transport network and from the protocols that are implemented therein. To this end, the invention provides a gateway between two networks and enabling communication to take place between services contained on applications servers situated on the first network and network elements forming the second network, it being possible for said network elements to be switching nodes or specialized resources, it being possible for said services to transmit requests to use the specialized resources to said gateway after a service call has been made by one of said switching nodes, the gateway having:
selection means for acting on receiving each of the requests by choosing a specialized resource from among the specialized resources by means of a representation (V) of the second network; and
connection means for implementing the necessary interchange with the network elements so as to set up a connection between the switching node from which the service call is made and the specialized resource.
In particular embodiments of the gateway of the invention, said gateway may include one or more of the following characteristics:
the representation contains a correspondence table between the network elements and the communications protocols they support;
the representation contains a correspondence table between the switching nodes and the specialized resources; and
the specialized resources are intelligent peripherals, the switching nodes are service switching points, and the applications servers are service control points, in compliance with the recommendations of the Q.1200 series by ITU-T.
The invention also provides a method of connecting a switching node to a specialized resource from among a set of available specialized resources, on request from a service that has been called by said switching node, said service being contained by an applications server. The method including the following steps in order:
the service transmits a request to use a specialized resource to a gateway;
the gateway chooses a specialized resource from said set; and
the gateway sets up the connection between the switching node and the specialized resource.
The invention also provides an intelligent network including at least one gateway of the invention.
A first advantage of the invention is that new services can be developed and deployed on the SCPs independently from the topology of the transport network, and more particularly from the relative disposition of the intelligent peripherals and of the SSPs, as well as from the communications protocol(s) used on the signalling network.
Another advantage, resulting from the first advantage, is that it is easily possible to manage a plurality of different protocols, e.g. different versions of INAP, for the same service.